The invention relates to a breath-actuated dry powder inhaler for administering dry powder medicament to a patient. More particularly, the present disclosure relates to a magazine having a plurality of individually separated, pre-metered doses for a breath-actuated dry powder inhaler and a method for providing pre-metered doses of dry powder medicament for inhalation by a patient.
Metered dose medicament inhalers are well known for dispensing medicament to the lungs of a patient. In most cases, the inhalers include a reservoir containing dry powder medicament in bulk form, and means for metering the medicament from the reservoir in discrete amounts for inhalation by a patient.
For example, U.S. Pat. No. 5,503,144, which is assigned to the assignee of the present disclosure and incorporated herein by reference, shows a breath-actuated dry-powder inhaler having a medicament reservoir. The reservoir contains dry-powder medicament in bulk form, and the inhaler includes a metering chamber for removal of the powdered medicament from the reservoir in discrete amounts. The inhaler also includes an air inlet for entraining the removed powdered medicament through a mouthpiece upon patient inhalation.
While the reservoir and metering chamber of the inhaler shown by U.S. Pat. No. 5,503,144 properly function to dispense discrete amounts of powdered medicament to a patient, there is desired an inhaler having pre-metered doses of powdered medicament. Providing the powdered medicament in pre-metered doses will further ensure that the medicament is consistently dispensed to a patient in precise doses.
In particular, a device and method are desired for providing individually sealed, pre-metered doses of dry powder medicament for inhalation by a patient through a dry powder inhaler and, in particular, a breath-actuated, dry powder inhaler.
An improved breath-actuated, dry powder inhaler, which substantially de-agglomerates and micronizes pre-metered doses of medicament is also desired to ensure that particles of the medicament are small enough for adequate penetration of the medicament into a bronchial region of a patient""s lungs during inhalation.
The present disclosure accordingly provides a pre-metered dose assembly for consistently supplying precise doses of medicament to a breath-actuated dry powder inhaler. The assembly includes a cap defining a dry powder delivery passageway for providing air to a dry powder supply port of a swirl chamber of a breath-actuated dry powder inhaler, and a magazine including a plurality of reservoirs for holding pre-metered doses of dry powder. One of the magazine and the cap is movable with respect to the other of the magazine and the cap for sequentially positioning the reservoirs within the delivery passageway of the cap. A breath-induced low pressure at an outlet port of the swirl chamber of the inhaler causes an air flow through the dry powder delivery passageway of the assembly and into the dry powder supply port of the swirl chamber. The air flow entrains dry powder from the reservoir positioned in the passageway for inhalation by a patient using the inhaler.
The present disclosure also provides a breath-actuated dry powder inhaler including the pre-metered dose assembly in combination with a de-agglomerator for breaking up aggregates and micronizing particles of dry powder prior to inhalation of the powder by a patient. The de-agglomerator includes an inner wall defining a swirl chamber extending along an axis from a first end to a second end, a dry powder supply port, one or more primary air flow inlet ports, and an outlet port. The supply port is at the first end of the swirl chamber for providing fluid communication between the dry powder delivery passageway of the pre-metered dose assembly and the first end of the swirl chamber. The primary air flow inlet ports are in the inner wall of the swirl chamber adjacent to or near the first end of the swirl chamber and provide fluid communication between a region exterior to the de-agglomerator and the swirl chamber. The outlet port provides fluid communication between the second end of the swirl chamber and a region exterior to the de-agglomerator.
A breath-induced low pressure at the outlet port of the de-agglomerator causes air flows into the swirl chamber through the dry powder supply port and the inlet port. The air flows collide with each other and with the wall of the swirl chamber prior to exiting through the outlet port, such that any powder entrained in the air flows is broken down and micronized. The de-agglomerator further includes vanes at the first end of the swirl chamber for creating additional collisions and impacts of entrained powder.
Further features and advantages of the presently disclosed pre-metered dose magazine and method for providing pre-metered doses will become more readily apparent to those having ordinary skill in the art to which the present disclosure relates from the following detailed description and attached drawings.